GBK51948 RHINO2
Installation Manual Issue 5
6.5.3.18 HW Current Limit Decel Scalar
Parameter Possible Values Default HHP Lite Std Adv
HW Current Limit Decel Scalar 6 – 94% 56% (DS90)
✓
This parameter is applied if the hardware current limit is exceeded due to regenerative
currents. If the SW Current Limit Decel Scalar cannot reduce the current enough, and the
current increases further, then this parameter will come into effect, and thereby reducing
the deceleration rate of the scooter further. This parameter should be set below the SW
Current Limit Decel Scalar, but still as high as possible to minimise the impact on stopping
distance.
Current Limit Deceleration Scalars Explained
Regenerative currents occur when the scooter decelerates, and if uncontrolled, they can
easily exceed two or three times the maximum current of the controller. If regenerative
currents are too high for too long, the controller will shut down the motor and apply the
park brake (i.e. slam stop) to prevent damage to the motor and the controller. In this
instance, the controller will show flash code 4 and the Wizard will report OVER_CURRENT
when it applies slam stop. The best way to avoid excessive regenerative currents is to
reduce the deceleration rates, in particular Emergency Deceleration, to the lowest
acceptable values.
To prevent the controller from performing a slam stop, deceleration scalars are applied
before the regenerative current becomes too high. The SW Current Limit Decel Scalar is
applied first when the current exceeds the maximum programmed motor current limit. The
effect of this is a reduction of the deceleration rate that will, in turn, reduce the increase of
the current. If the current continues to increase further (around 30A), the HW Current Limit
Decel Scalar is applied. This will reduce the deceleration rate even further. Note that the
value of HW Current Limit Decel Scalar must be set lower than SW Current Limit Decel
Scalar.
If these scalars are set as low as possible, the lifetime of the controller and the motor is
extended and the long-time performance is not affected (no FET degrading). However,
these scalars will affect stopping distance: smaller scalar values will increase the stopping
distance. As guidance and a starting point, set the scalars as follows:
l
for small scooters (maximum current 90A):
l
SW Current Limit Decel Scalar: 75%
l
HW Current Limit Decel Scalar: 50%
l
for medium sized scooters (120A):
l
SW Current Limit Decel Scalar: 69%
l
HW Current Limit Decel Scalar: 44%
l
for large scooters (160A):
l
SW Current Limit Decel Scalar: 56%
l
HW Current Limit Decel Scalar: 31%
Page 92 - Programming
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